Leaf blight disease severely constrains the production of taro (Colocasia esculenta (L.) Schott) in Cameroon. Studies were conducted in seven localities in Fako Division, South West Region of Cameroon to assess the incidence and severity of the disease in taro farms using non-destructive sampling, and to document farmers’ knowledge about it using a structured questionnaire. The fungicidal effect of the aqueous leaf extract of goatweed (Ageratum conyzoides L.) at 0 and 100% concentrations and the chemical fungicide Mancozan was tested in-vitro. Results revealed widespread distribution of the disease in the Region. The incidence (77.996.5%) and severity (51.9 – 85.6%) varied significantly (P≤0.05) across the localities. The infection rate was classified as high in four localities and very high in three. The farmers were able to identify the disease and understood its effects on taro production but they were not aware of any pesticidal plants for its management. The aqueous leaf extract (100%) of goatweed and Mancozan significantly (P≤0.05) inhibited the mycelia growth of the fungus compared to the untreated control (0%). The plant extract had the potential to control the disease although it gave moderate inhibition of the fungus (38.4% at 9 days after exposure) which was not as effective as Mancozan (100% inhibition). Goatweed could be exploited for use as a source of natural fungicide for management of the pathogen. This study provides baseline information for future studies on the disease and recognises it as a major challenge to the sustainable production of taro.

Taro leaf blight (TLB), a major disease of taro plant caused by Phytophthora colocasiae, a pseudo-fungus, that occurs in many taro producing areas, especially in the South West of Cameroon. A Survey was conducted to assess farmers’ knowledge, as well as to determine the incidence and the severity of the disease in taro fields. Structured questionnaires were administered in selected locations (Bokova, Ekona, Muea, Mile 16, Mutengene, and Likomba) of taro production. Two farms were selected with two quadrats of 64 m2 each were carved to assess disease incidence and severity on taro. The number of plants infected with taro leaf blight were counted and the area of the affected leaves measured was used to evaluate the disease incidence and disease severity. Data collected were subjected to ANOVA for complete randomized design and the means were compared using Tukey test at 0.05 probability levels. The results revealed that most of the farmers could identify the disease while practicing cultural methods in controlling the disease. The results also revealed significant differences (p = 0.001) in disease incidence and disease severity in all the localities, with Mile 16 showing the highest percentage mean of 96.53% and 85.59%, respectively. The severity scored showed high infection range of 3 – 3.95 in all locations except in Likomba (2.60).  It could be concluded from the results that there were high prevalence of taro leaf blight disease in Fako Division. Good management strategies are therefore required to control Taro leaf blight and improve taro production in the area.